Sediment-transport experiments in zero-gravity

One of the important parameters in the analysis of sediment entrainment and transport is gravitational attraction. The availability of a laboratory in earth orbit would afford an opportunity to conduct experiments in zero and variable gravity environments. Elimination of gravitational attraction as a factor in such experiments would enable other critical parameters (such as particle cohesion and aerodynamic forces) to be evaluated much more accurately. A Carousel Wind Tunnel (CWT) is proposed for use in conducting experiments concerning sediment particle entrainment and transport in a space station. In order to test the concept of this wind tunnel design a one third scale model CWT was constructed and calibrated. Experiments were conducted in the prototype to determine the feasibility of studying various aeolian processes and the results were compared with various numerical analysis. Several types of experiments appear to be feasible utilizing the proposed apparatus

Development and testing of a unique carousel wind tunnel to experimentally determine the effect of gravity and the interparticle force on the physics of wind-blown particles

In the study of planetary aeolian processes the effect of gravity is not readily modeled. Gravity appears in the equations of particle motion along with the interparticle forces but the two are not separable. A wind tunnel that perimits multiphase flow experiments with wind blown particles at variable gravity was built and experiments were conducted at reduced gravity. The equations of particle motion initiation (saltation threshold) with variable gravity were experimentally verified and the interparticle force was separated. A uniquely design Carousel Wind Tunnel (CWT) allows for the long flow distance in a small sized tunnel since the test section if a continuous loop and develops the required turbulent boundary layer. A prototype model of the tunnel where only the inner drum rotates was built and tested in the KC-135 Weightless Wonder 4 zero-g aircraft. Future work includes further experiments with walnut shell in the KC-135 which sharply graded particles of widely varying median sizes including very small particles to see how interparticle force varies with particle size, and also experiments with other aeolian material

Aeolian processes aboard a Space Station: Saltation and particle trajectory analysis

The Carousel Wind Tunnel (CWT) proposed to study aeolian processes aboard a Space Station consists of two concentric rotating drums. The space between the two drums comprises the wind tunnel section. Differential rates of rotation of the two drums would provide a wind velocity with respect to either drum surface. Preliminary results of measured velocity profiles made in a CWT prototype indicate that the wall bounded boundary layer profiles are suitable to simuate flat plate turbulent boundary layer flow. The two dimensional flate plate Cartesian coordinate equations of motion of a particle moving through the air are explained. In order to assess the suitability of CWT in the analysis of the trajectories of windblown particles, a series of calculations were conducted comparing cases for gravity with those of zero gravity. Results from the calculations demonstrate that a wind tunnel of the carousel design could be fabricated to operate in a space station environment and that experiments could be conducted which would yield significant results contributing to the understanding of the physics of particle dynamics

Dust devils on Earth and Mars: Extension of particle threshold laboratory simulations

Abstract not available

Physics of windblown particles

A laboratory facility proposed for the Space Station to investigate fundamental aspects of windblown particles is described. The experiments would take advantage of the environment afforded in earth orbit and would be an extension of research currently being conducted on the geology and physics of windblown sediments on earth, Mars, and Venus. Aeolian (wind) processes are reviewed in the planetary context, the scientific rational is given for specific experiments to be conducted, the experiment apparatus (the Carousel Wind Tunnel, or CWT) is described, and a plan presented for implementing the proposed research program

Reporting of Harm in Randomized Controlled Trials of Therapeutic Exercise for Knee Osteoarthritis: A Systematic Review

Objective: The Consolidated Standards of Reporting Trials (CONSORT) recommends reporting adverse events (AEs) and dropouts (DOs) with their definitions. The purpose of this study was to identify how AEs and DOs were reported in randomized controlled trials (RCTs) of therapeutic exercise for knee osteoarthritis (OA). Methods: Data sources were the Cochrane Library, EMBASE, PUBMED, and CINAHL. Databases were searched to identify RCTs of therapeutic exercise for Knee OA published from January 1, 1980, through July 23, 2020. Researchers independently extracted participant and intervention characteristics and determined whether a clear statement of and reasons for AEs and DOs existed. The primary outcome was exercise-related harm. Physiotherapy Evidence Database (PEDro) scoring described study quality and risk of bias. Descriptive and inferential statistics characterized results. Meta-analysis was not performed due to data heterogeneity. Results: One hundred 13 studies (152 arms) from 25 countries were included with 5909 participants exercising. PEDro scores ranged from 4 to 9. Exercise intensity was not specified in 57.9% of exercise arms. Fifty studies (44.2%) included an AE statement and 24 (21.2%) reported AEs, yielding 297 patients. One hundred three studies (91.2%) had a DO statement. Sixteen studies (15.5%) provided reasons for DOs that could be classified as AEs among 39 patients, yielding a 13.1% increase in AEs. Thus, 336 patients (6.0%) experienced exercise-related harm among studies with a clear statement of AEs and DOs. A significant difference existed in misclassification of DOs pre- and post-CONSORT 2010 (12.2% vs 3.1%; X21 = 21.2). Conclusions: In some studies, the reason for DOs could be considered AEs, leading to potential underreporting of harm. Improvements in reporting of harm were found pre-and post-CONSORT 2010. Greater clarity regarding AE and DO definitions and TherEx intensity are needed to determine safe dosing and mode of therapeutic exercise for knee OA. Impact: More adherence to the CONSORT statement is needed regarding reporting of and defining AEs, DOs, and therapeutic exercise intensity; however, despite this, therapeutic exercise seems to be associated with minimal risk of harm

The quality of intervention reporting in trials of therapeutic exercise for hip osteoarthritis: a secondary analysis of a systematic review

Background: Therapeutic exercise is recommended as a core treatment for hip osteoarthritis (HOA). Whilst it is widely accepted that exercise can improve pain and disability, optimal type and dose of exercise are yet to be agreed upon. This may, in part, be attributed to the wide variation and inadequate reporting of interventions within the literature. This study evaluates the quality of intervention reporting among trials of therapeutic exercise in HOA. Methods: Randomised controlled trials (RCTs) were sourced in a systematic review, completed in August 2020. Two raters independently used the Template for Intervention Description and Replication (TIDieR) and Consensus on Exercise Reporting Template (CERT) to evaluate intervention reporting. Correlations between quality assessment scores and CERT and TIDieR scores evaluated the relationship between internal validity and external applicability. The year of publication was compared to the quality of reporting scores. Results: Fourteen RCTs were included in the analysis. On average, studies were awarded 9.43 ± 1.95 out of 12 points for the TIDieR checklist (range 4–12) and 13.57 ± 4.01 out of 19 points for the CERT (range 5–19). Pearson’s correlation coefficient suggested that the quality of reporting had improved over time and that there was a fair, positive relationship between internal validity and external applicability. Discussion: Whilst the quality of intervention reporting is improving, many RCTs of therapeutic exercise in HOA lack the detail necessary to allow accurate evaluation and replication. Researchers are encouraged to utilise the standardised reporting guidelines to increase the translation of effective interventions into clinical practice

Automated interpretation of systolic and diastolic function on the echocardiogram:a multicohort study

Background: Echocardiography is the diagnostic modality for assessing cardiac systolic and diastolic function to diagnose and manage heart failure. However, manual interpretation of echocardiograms can be time consuming and subject to human error. Therefore, we developed a fully automated deep learning workflow to classify, segment, and annotate two-dimensional (2D) videos and Doppler modalities in echocardiograms. Methods: We developed the workflow using a training dataset of 1145 echocardiograms and an internal test set of 406 echocardiograms from the prospective heart failure research platform (Asian Network for Translational Research and Cardiovascular Trials; ATTRaCT) in Asia, with previous manual tracings by expert sonographers. We validated the workflow against manual measurements in a curated dataset from Canada (Alberta Heart Failure Etiology and Analysis Research Team; HEART; n=1029 echocardiograms), a real-world dataset from Taiwan (n=31 241), the US-based EchoNet-Dynamic dataset (n=10 030), and in an independent prospective assessment of the Asian (ATTRaCT) and Canadian (Alberta HEART) datasets (n=142) with repeated independent measurements by two expert sonographers. Findings: In the ATTRaCT test set, the automated workflow classified 2D videos and Doppler modalities with accuracies (number of correct predictions divided by the total number of predictions) ranging from 0·91 to 0·99. Segmentations of the left ventricle and left atrium were accurate, with a mean Dice similarity coefficient greater than 93% for all. In the external datasets (n=1029 to 10 030 echocardiograms used as input), automated measurements showed good agreement with locally measured values, with a mean absolute error range of 9–25 mL for left ventricular volumes, 6–10% for left ventricular ejection fraction (LVEF), and 1·8–2·2 for the ratio of the mitral inflow E wave to the tissue Doppler e' wave (E/e' ratio); and reliably classified systolic dysfunction (LVEF <40%, area under the receiver operating characteristic curve [AUC] range 0·90–0·92) and diastolic dysfunction (E/e' ratio ≥13, AUC range 0·91–0·91), with narrow 95% CIs for AUC values. Independent prospective evaluation confirmed less variance of automated compared with human expert measurements, with all individual equivalence coefficients being less than 0 for all measurements. Interpretation: Deep learning algorithms can automatically annotate 2D videos and Doppler modalities with similar accuracy to manual measurements by expert sonographers. Use of an automated workflow might accelerate access, improve quality, and reduce costs in diagnosing and managing heart failure globally. Funding: A*STAR Biomedical Research Council and A*STAR Exploit Technologies

Mind, absent characters, and the deployment of ideology in Henry James’s short fiction

This paper examines the role of ideology in the construction of absent characters in Henry James’s short fiction against a methodological background of cognitive narratology and the attendant notions of metarepresentation, extended mind, and distributed identity. Building on the conviction that those minds that communally assemble absent characters by projecting subjective images of them do form identifiable ideological systems rather than arbitrary arrays, an approach to the construction of absent Louisa Brash in “The Beldonald Holbein” (1901) is made in the context of “Daisy Miller” (1878), “The Author of Beltraffio” (1884), and “The Next Time” (1895). Published in three different decades, these stories display absent and quasi‐absent characters who are conjured up for the reader in much the same way as Mrs. Brash is, namely as functions of a priori ideological positions based on sequenced degrees of commitment to the thematic dominant of a tale, a process that often results in deeply conflicted identities.US Fulbright Program/Spanish Ministry of Education, Culture, and Sport, Grant/Award Number: PRX16/00265